WORKSHOP 15 Restarting a Linear Static Analysis of a Simply- Supported Stiffened Plate Objectives: Submit a job to MSC.Nastran for analysis and save the restart files. (SCR = NO) Perform a restart on a model created from a previous workshop with a different loading. MSC.Nastran 120 Exercise Workbook 15-1
15-2 MSC.Nastran 120 Exercise Workbook
WORKSHOP 15 Stiffened Plate (Sol 101-Restart) Model Description: Restarts can be used to run additional load cases or obtain additional results using fewer hardware resources assuming the model and constraints remain unchanged, and the restart files are available. Using the model created from Workshop 10, create a new subcase using the original constraints and a body acceleration of 1g. Figure 15.1 - Model Schematics 1-g acceleration Stiffener 5.0 (typ) 0.1 b A A 20.0 2.0 a a 0.1 20.0 Y Z X View A-A b 1.0 Table 15.1 - Model Properties Elastic Modulus: 10.3E+06 psi Poisson Ratio: 0.3 Density: 0.101 lbs/in 3 Plate Thickness: 0.1 in Bar Cross-Sectional Area: 0.38 in 2 I aa : 0.2293 in 4 I bb : 0.0168 in 4 J: 0.0013 in 4 MSC.Nastran 120 Exercise Workbook 15-3
Exercise Procedure: 1. Edit the input file workshop15_work.bdf. This file is identical to the file created in Workshop 10. Save the modified input file as workshop15.bdf. 2. Submit this file to the MSC.Nastran solver for analysis. To do this, find an available xterm window and at the prompt enter: nastran workshop15.bdf NOTE: scr=yes is not used for this exercise; to perform a restart, the MSC.Nastran database and related files are needed. Monitor the run using the UNIX ps command. 3. When the analysis has completed successfully, use a text-editor to create a Restart input file called restart_workshop15.bdf with additional output requests for a new gravity load. DO NOT DELETE ANY FILES FROM THE FIRST MSC.Nastran RUN. 4. Important input: Entry Comments FMS ASSIGN RESTART Which database should be used for the restart? What version should be used? Case Control SUBCASE Specify a new load set what case control commands do this? Use 19 as the new SUBCASE identification number. LOAD DISPLACEMENT, STRESS Define a new loading condition and assign it to subcase. Extract displacements & stresses for the new load condition. Which output requests should be used? Bulk Data (PARAMs) GRAV Define gravitational load in the -z direction. 5. After creating the Restart file, submit this file to MSC.Nastran for analysis. To do this, find an available xterm window and at the prompt enter: 15-4 MSC.Nastran 120 Exercise Workbook
WORKSHOP 15 Stiffened Plate (Sol 101-Restart) nastran restart_workshop15.bdf scr=yes Monitor the run using the UNIX ps command. 5a. When the run is completed, edit the restart_workshop15.f06 file and search for the word FATAL. If none exists, search for the word WARNING. Determine whether or not existing WARNING messages indicate modeling errors. 5b. While still editing restart_workshop15.f06, search for the word: D I S P L A C E (spaces are necessary) What are the components of the displacement vector for GRID 83 for the new SUBCASE 19 (translation only)? disp X = disp Y = disp Z = Search for the word: S T R E S S (spaces are necessary) What is the axial stress for CBAR 146 for the new SUBCASE 19? axial stress = Search for the word: Q U A D (spaces are necessary) What are the centroidal Von Mises stresses for CQUAD4 77 for the new SUBCASE 20? -(thk/2): stress = +(thk/2): stress = MSC.Nastran 120 Exercise Workbook 15-5
6. Finally, visualize the results in MSC.Patran. Attach both model & results into a new MSC.Patran database from the restart_workshop15.xdb results file. Analysis Action: Attach XDB Object: Result Entities Method: Local Select Results File... Filter Selected Results File: OK Apply restart_workshop15.xdb When translation is completed and the Heartbeat turns green, bring up the Results form. Results Action: Create Object: Quick Plot Choose the desired result case in the Select Result Cases list and select the result(s) in the Select Fringe Result list and/or in the Select Deformation Result list. And hit Apply to view the result(s) in the viewport. To clean up the display, use the Reset Graphics tool. Reset Graphics Quit MSC.Patran after completing this exercise. 15-6 MSC.Nastran 120 Exercise Workbook